Pogo stick with adjustable spring bias

ABSTRACT

The specification discloses a pogo stick in which the spring is adjustable and which includes a latch which will hold the stick in collapsed position and which can be selectively released to permit operation of the stick. The spring can be adjusted manually or automatically.

United States Patent 1 Samiran et al.

[451 Nov. 20, 1973 POGO STICK WITH ADJUSTABLE SPRING BIAS [76] Inventors: David Samiran,l48 Northwest Road; Arthur H. Moore, 46 Northwest Road, both of Westfield, Mass.

[22] Filed: Nov. 29, 1971 [21] Appl. No.: 202,831

[52] U.S. Cl. 272/57 E, 267/177 [51] Int. Cl A63b 25/08 [58] Field of Search 272/57 E; 135/64;

[56] References Cited UNITED STATES PATENTS 2,871,016 l/l959 Rapaport 272/57 E 1,406,453 2/ 1922 Fanning 3,110,492 11/1963 Hoffmeister 272/57 3,206,153 9/1965 Burke 267/177 X FOREIGN PATENTS OR APPLICATIONS 4,931 9/1905 France 267/177 Primary Examiner-Anton O. Oechsle Att0rneyJeffers & Rickert [5 7 ABSTRACT The specification discloses a pogo stick in which the spring is adjustable and which includes a latch which will hold the stick in collapsed position and which can be selectively released to permit operation of the stick. The spring can be adjusted manually or automatically.

21 Claims, 12 Drawing Figures SHEET u 0F 5 PATENTEUHUVPU I975 INVENTORg ARTHUR HM QRE: DAv\o SAMmAu U cleffers Q ker-t A'flornevs FIG.6

1 POGO STICK WITH ADJUSTABLE SPRING BIAS The present invention relates to pogo sticks, and is particularly concerned with an improved pogo stick construction in which the spring force acting on the telescopic members making up the pogo stick can be adjusted and which includes a latch for holding the pogo stick in collapsed condition.

Pogo sticks are, of course, well known and comprise an upper member, which is tubular, having a hand graspable portion at the upper end and having foot engaging portions at the lower end. Telescopically and slidably fitted into the lower end of the upper member is a lower member having a ground engaging element at the lower end and with a spring being provided acting axially between the tubular members.

The present invention is concerned with a pogo stick of the general nature referred to above except that the stick includes additional devices for making the stick more adaptable to individuals of different weight and for adapting the stick to different desired operating characteristics and also for making the stick simpler to use.

Accordingly, a primary objective of the present invention is the provision of a pogo stick in which the spring portion acting on the telescoping members of the stick is adjustable.

Another object of the invention is the provision of a pogo stick with a biasing spring therein, the bias of which can be adjusted either manually or automatically as the stick operates.

A further object of the invention is the provision of a pogo stick which can be latched in collapsed position thereby making the stick relatively easy to use.

These and other objects and advantages of the present invention will become more apparent upon reference to the following detailed specification taken in connection with the accompanying drawings in which:

FIG. 1 is an elevational view showing a pogo stick constructed according to the present invention;

FIG. 2A is a vertical section taken on line 22 of FIG. 1 of the upper portion of the stick and drawn at enlarged scale;

FIG. 2B is a vertical section taken on line 2-2 of FIG. 1 of the lower portion of the stick and drawn at enlarged scale;

FIG. 3 is a plan sectional view on line 3-3 of FIG. 2A;

FIG. 4 is a side elevational view of the ratchet assembly of FIG. 3;

FIG. 5 is a vertical section through a slip clutch employed in the structure;

FIG. 6 is a side view of a plate forming a part of the structure of FIG. 2;

FIGS. 7A and 7B are views like FIGS. 2A and 2B, but show a modified construction;

FIG. 8 is a fragmentary view showing a modification;

FIG. 9 is a fragmentary view showing the stick in the compressed and locked position; and 1 FIG. 10 is a fragmentary view showing the stick in the compressed position but being unlocked.

BRIEF SUMMARY OF THE INVENTION According to the present invention, a pogo stick structure is provided which consists of an upper member, preferably tubular, having a hand grip at the upper end and foot rests at the lower end and a lower member slidably telescoping into the lower end of the upper member and having a ground engaging pad on the lower end. A spring in the upper member bears axially between the members and urges the members toward extended position.

At least one end of the spring bears on a plate which is, in turn, engaged by an axial screw so that rotation of the screw willadjust the plate axially and thereby adjust the bias of the spring.

A connection with the screw permits manual rotation thereof and there may be, furthermore, an automatic drive for the screw which operates in response to relative telescopic movements of the lower and upper members and which is connected with the screw via a reversible clutch and a slip clutch.

For making the stick easy, and safe, to use, a latch is provided which latches the members together in a position of maximum telescopic engagement and is arranged to be operated into effective and ineffective positions in response to tilting of the pogo stick when the full weight of the user is supported on the foot rests of the stick.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings somewhat more in detail, FIG. 1 is a small elevational view showing a pogo stick according to the present invention and which consists of an upper tubular member 10 having a hand grip or hand graspable element 12 on the upper end and foot engageable means 14 on the lower end. The foot engageable means comprises a bracket 16 fixed to a heavy tubular member 17 fixed to and forming the lower end part of tubular member 10 and foot rests 18 pivotally mounted thereon for movement between folded down horizontal working positions and folded up vertical idle positions.

ExtendingQupwardly into the lowerend of upper tubular member 10 is a lower member 20, which may also be at least partially tubular, and which at the lower end has a ground engaging pad 22 thereon. The underside of pad 22 is cut off at an angle so as to diverge from the horizontal in a direction away from the user of the stick.

Inside tubular member 10, as will be seen in FIG. 2, is a compression spring 24 which at its lower end bears on a plate 26 nonrotatably mounted in the upper tubular member 10. At its upper end, spring 24 bears on nonrotatable outer part 28 of a ratchet drive, or clutch, to be described hereinafter.

An axial screw 30 is provided in member 10 which threadedly ehgages plate 26. The screw at its lower end is fixed to nuts 31 which are rotatably retained on the upper end of lower member 20 by a cap 33. The upper end of member 20 also has a shoulder 35 thereon which engages the upper end of tubular member 17 when the stick is in fully extended position.

At its upper end, screw 30 has connected thereto one element of a slip clutch 34, the other element of which is connected to the lower end of an axially extending spiral strip 36, the upper end of which extends into the inner part 29 of the aforementioned ratchet drive, or one way clutch, which also comprises the aforementioned outer part 28.

As will become apparent hereinafter, the ratchet drive, or one way clutch, is reversible and in response to relative reciprocation of members 10 and 20, will cause strip 36 to rotate in one direction or the other,

or to take no rotation, as members and reciprocate relatively. Any such rotation of strip 36 is imparted to screw 36 via slip clutch 34 and this will cause adjustment of plate 26 in one axial direction or the other and thereby change the bias of spring 24 on members 10 and 20.

The foot rests 18 are carried on a shaft 19 which is tiltable in the support bracket 21 which carries the shaft and which bracket is secured to one side of member 17, as by the U boltarrangement 23.

Bracket 21 and member 17 define a longitudinal cavity in which a spring blade 38 is disposed with the upper end carrying a button 40 and with the lower end connected to shaft 19. Button 40 is disposed adjacent an aperture, or slot 46, formed in tubular element 41 which is fixed to member 17 and these form a part of member 10 and slidably receives member 20. Aperture 7 to rotate shaft 19, or by inclining the stick toward the user while holding the foot rests against rotation by the weight of the user, and with the stick fully collapsed, the button 40 will push plunger 48 out of aperture 46 and thereby release members 10 and 20 for relative reciprocation.

So long as the stick is maintained in a substantially vertical position, the plunger 48 will be prevented from reentering aperture 46 but on inclining the stick away from the user, the plunger will enter the aperture when the stick is collapsed and latch members 10 and 20 together.

The provision of the latch makes it quite simple to place the stick in operation as opposed to pogo sticks according to the prior art which were normally in extended position when placed in use.

It will be noted that plunger 48 has an annular groove 52 therein near the outer edge which engages aperture 46 in tubular element 41 whereby the latch is retained in latching position until released therefrom by placing the full weight of the user on the foot rests on upper member 10 while simultaneously tilting the stick toward the user.

The end of plunger 48 that extends through aperture 46 is longer below center than above center. The latch arrangement forms a safety feature because a user must be of sufficient height to release the latch before the stick can be used.

Relative rotation between members 10 and 20 can be prevented as by dog 54 on member 10 which engages axial slot 56 in member 20.

Inner part 29 of the ratchet drive has a tubular extension 60 extending axially through hand grip l2 and slidably and tiltably but nonrotatably connected to the upper end thereof is a crank 62 rotatably connected to cap 64 threaded into and forming the upper end of hand grip 12. By unthreading cap 64, crank 62 can be pulled out and tilted about the axis of connecting pin 66 and then utilized for rotating tubular extension 60 and inner part 29 of the one-way clutch thereby to adjust screw 30 manually.

Inasmuch as crank 62 is freely rotatable in cap 64, the provision of the crank on tubular extension 60 does not in any way interfere with the operation of the oneway clutch when the stick is in use and cap 64 is threaded into hand grip 12. v

At the bottom of hand grip 12 is an adjusting element 68 having a neutral position wherein inner part 29 of the ratchet driveis freely rotatable in both directions. Adjusting element 68 has two adjusted positions in each of which the inner part 29 of the ratchet drive is restrained against rotation in a respective direction so that screw 30 can either be selectively driven in one rotation or the other during operation of the stick. Element 68 is secured by screws 69 to a ring 71 rotatable on outer part 28 of the one-way, or reversible, clutch and which is fixed to bottom of handle 12. Tubular member 10 is seated circumferentially to permit element 68 and part 28 to rotate together with screws 69.

The connection between outer and inner parts 28 and 29 respectively of the one-way clutch is shown at FIGS. 3 and 4. n will be noted in FIGS. 3 and 4 that inner part 29 comprises ratchet teeth about the periphery thereof whereas outer part 28 has pivotally mounted therein a two armed ratchet lever 72. The

ratchet lever has angularly disposed outer faces 74 thereon engaged by a spring blade 76. Spring blade 76 is connected with ring 71 attached to adjusting element 68 by screws 69 so as to be rotated in' response to angular adjustment of adjusting element 68.

Two-arm lever 72 can, thus, be held in its FIG. 3 position to permit free rotation of inner part 29 in both directions or it can be adjusted into position wherein either of the ends of the arms of lever 72 engage the periphery of inner part 29 so as to ratchet over teeth 70 in a respective direction of rotation of part 29 while preventing rotation of part 29 in the opposite direction.

The slip clutch 34 is shown more in detail in FIG. 5 and will be seen to comprise an upper element 80 adapted for connection to the lower end of the spiral strip and a lower element 82 adapted for being threaded on the upper end of screw 30 and fixed in place by a lock nut 83.

Engaging the lower end of element 80 is a friction disc 84 which also engages a disc 86 nonrotatably connected by pins 88 with upper tubular part 90 of lower element 82. A cup 91 extends into a cavity in the end of screw 30 and has a flange engaging the end of the screw. A spring 92 in cup 91 urges disc 86 upwardly so friction disc 84 will predetermine the torqueat which the slip coupling will slip.

Upper element 80 is axially located in part 90 as by pin means 94 which connect collar 95 to part 90. Collar 95 is rotatable on element 80 so as not to interfere with the operation of the slip coupling.

The nonrotatability of the plate 26 in tubular member 10 is effected by the arrangement shown in FIG. 6, which will show that plate 26 is formed with an annular groove in which is seated a coil spring 102 which consists of just under two convolutions and which is notched between the opposed ends of the convolutions and is held against rotation in groove 100 by a lock plate 104. Plate 26, it will be appreciated, is a nut which is held against rotation without the use of a key and slot.

By this arrangement, if the plate 26 tends to turn in either direction in member 10, one convolution of the spring 102 will expand and bind in member and thereby prevent the said rotation. The spring, at least near the ends, presses against the inside of member 10 and produces the aforesaid action. The spring arrangement thus permits free axial movement of plate 26 in member 10, but prevents any substantial rotation thereof in either direction in member 10.

From the foregoing, it will be apparent that the bias of spring 24 in the stick can readily be adjusted manually to any desired degree and that, furthermore, by availing of the one-way clutch provided, the bias of the spring can be caused to increase or decrease during operation of the stick due to the reciprocation of the spiral strip in the one-way clutch. Also, by setting the selector element for the clutch in a neutral position, adjustment of the spring during operation of the stick can be prevented.

The pogo stick shown in FIG. 7 is substantially the same as that shown in FIG. 2 except that certain parts are inverted.

In FIG. 7, the upper tubular member 120 has a block 122 fixed therein to which hand grip 124 is connected. Block 122 rotatably but nonaxially moveably supports the upper end of screw 126. Slidably mounted on an extension of screw 126 at the upper end is a drive tube 128 having a crank 130 pinned thereto which can be drawn outwardly at the top of the handle by unthreading cap 132. When the crank is drawn outwardly from the handle, it can be tilted over and employed for rotating the screw, but when cap 132 is in its FIG. 7 position, crank 130 does not interfere with rotation of the screw.

The plate 134, nonrotatable in upper member 120 and threadedly engaged by the screw, is in the upper end of tubular member 120. The lower end of the screw is connected by a slip clutch 136 with the upper end of spiral strip 138 that extends reciprocably but nonrotatably through inner part 140 of a ratchet assembly that includes a nonrotatable outer part 142 fixed to the upper end of lower member 144 of the stick assembly.

A selector member 146 is rotatably mounted on upper member 120 in the range of the ratchet assembly and is operable for adjusting the ratchet assembly for opposite directions of drive and into a neutral position. Member 146 carries a plunger 147 biased outwardly by a spring 149. By pressing plunger 147 inwardly, it will engage a hole in the ring 151 and, due to a circumferential slot in tubular member 120, ring 151 can be rotated so the spring finger 153 thereon can adjust clutch pawl 155. In all other respects, the assembly of FIG. 7 is the same as that of FIG. 2 and operates in the same manner and, accordingly, no description thereof is given.

' The modification of FIG. 8 pertains to the operation of the latch which holds the parts of the stick in collapsed position. In FIG. 8, the lower part 150 of the stick, as before, carries a latch plunger 152 adapted to engage an aperture 154 in a tubular element forming a part of the upper member of the stick assembly. The button 156 on the end of spring arm 158 is moveable axially of aperture 154 to permit lock plunger 152 to enter the aperture or to push it therefrom.

Arm 158 is connected with shaft 160 on which the foot rests are mounted so as to be rotated by the foot rests. In the modification of FIG. 8, an additional spring 162 is provided between arm 158 and the side of the cavity in which arm 158 is disposed. i

This additional spring 162 normally biases arm 158 so that it holds button 156 in ineffective position, with a greater force than the previous modification. However, an adjusting screw 164 isprovided which, upon being threaded inwardly, will push arm 158 toward aperture 154 and position button 156 so that it will prevent locking plunger 152 from entering the said aperture. The provision of spring 162 is a safety feature because it makes shaft very difficult to turn by hand. Only the full weight of the user on the foot rests can turn shaft 160 when screw 164 is in retracted position.

In operation, assuming the upper and lower parts of the pogo stick are latched together, the stick can be placed in operation by an individual standing on the foot rests and then tilting the stick toward himself which will cause the unlocking mechanism connected with the foot rests to dislodge the locking plunger, so that the two parts of the stick are free to reciprocate. The stick can then be used in a conventional manner and can be stopped with the two parts locked in a position near maximum telescopic engagement by tilting the stick away from the user at an angle of, say, 5 to 10.

The user of the stick can readily preset the spring bias by availing of the crank contained in the handgrip and can cause the spring tension gradually to increase or decrease or to remain unchanged during the use of the stick by adjustment of the ratchet drive mechanism.

The slip clutch slips at a certain torque and prevents any damage to any part of the apparatus should the plate on the screw reach a limit position during operation of the ratchet assembly in drive condition.

As mentioned, the stick can be made without automatic adjustment of the spring, in which case the spring could be adjusted manually.

Modifications may be made within the scope of the appended claims.

What is claimed is:

l. A pogo stick comprising, in combination, an upper tubular member having hand graspable means on the upper end and tiltable foot engageable means on the lower end, a lower tubular member having ground engaging means on the lower end and having the upper end extending into the lower end of said upper tubular member in slidable telescopic relation thereto, a spring in said upper tubular member bearing axially between said tubular members and urging the tubular members toward extended positions, adjusting means for adjusting the bias exerted by said spring on said tubular members, said adjustment means including a slidable plate mounted in the upper tubular member and forming a bearing for the adjacent end of said spring, an axial screw rotatably but nonaxially movable connected at one end to one of said tubular members and threadedly engaging said plate, means for preventing rotation of said slidable plate within said upper tubular member, said rotation preventing means including a spring disposed in a groove in said plate in such manner as to engage the interior of the upper tubular member in such manner as to prevent rotation of the plate and actuating means for rotating said screw to adjust said slidable plate axially in said upper tubular member and thereby adjust the bias of said spring on said tubular members.

2. A pogo stick according to claim 1 wherein the actuating means includes manual means connected to said screw and carried by said upper tubular member for rotating the screw relative to said slidable plate.

3. A pogo stick according to claim 2 in which said manual means includes means extending through said hand graspable means and operatively connected to said screw for selectively rotating said screw and for permitting said screw to rotate-relative to said hand graspable means.

4. A pogo stick according to claim 1 wherein the actuating means includes ratchet drive means connected to said screw and responsive to relative axial movement 'of said'tubular members for rotating said screw relative tosaid slidable plate.

5. A pogo stick according to claim 4 which includes slip clutch means in the connection of said drive means tosaid screw and slipable at a predetermined torque.

\ 6. A pogo stick according to claim-4 in which said drive means is reversible.

7. A pogo stick according to claim 4 in-which said drive means includes means for selective adjustment thereof into ineffective position and into position to drive said screw in either direction.

8. A pogo stick according to claim 4 in which said drive means includes an axially extending spiral strip connected at one end to the end of said screw opposite the end thereof connected to said one member, an element having a slot engaged by said spiral strip and nonaxially moveably connected to the other of said members, and a one-way clutch connecting said element and the other of said members.

9. A pogo stick according to claim 8 in which said clutch is reversible and includes a selector adjustable into a position for each drive direction of said clutch and into a position wherein said clutch is ineffective in both directions.

10. A pogo stick according to claim 9 in which said slip clutch means is interposed in the connection of said strip to said screw.

11. A pogo stick according to claim 1 which includes latch means selectively operable by tilting said foot means for latching said upper and lower members together in a predetermined position near the position of maximum telescopic engagement thereof.

12. A pogo stick according to claim 1] in which said latch means comprises a spring biased plunger on said lower member and an aperture in said upper member engageable by the plunger, a spring arm having an element on one end engageable with said plunger to dislodge the plunger from the aperture, a shaft connected to the other end of said arm and having said foot engageable means thereon, said shaft being rotatably supported on said upper member.

her, a plate non-rotatably but recipocablly mounted in said upper member and engaging one end of said spring, a ratchet assembly engaging the other end of said spring, said ratchet assembly having a first nonrotatable part and a second part rotatable on the first part and cooperating elements of a ratchet on said parts, said second part having a diametral slit therein, a screw extending axially of said upper member and threadedly engaging said plate, one end of said screw being rotatably but nonaxially moveably connected to one of said upper and lower members and said first part of said ratchet assembly being fixed to the other of said members, a spiral strip having one end reciprocably but nonrotatively engaging said slit in said second part of said ratchet assembly and means drivingly connecting the other end of said strip to the free end of said screw.

14. A pogo stick according to claim 13 which includes means moveable on said upper member and operable to adjust said elements of a ratchet relatively to permit free rotation of said second part on said first part in both directions or to permit free rotation of said second part on said first part in a respective direction while preventing rotation thereof in the opposite directron.

15. A pogo stick according to claim 13 which includes means selectively operable for manually rotating said screw.

16. A pogo stick according to claim 13 which includes latch means selectively operable for latching said upper and lower members together in a predetermined position near the position of maximum telescopic engagement thereof.

17. A pogo stick according to claim 16 in which said latch means comprises a spring biased plunger on said lower member and an aperture in said upper member engageable by the plunger, a spring arm having an element on one end engageable withsaid plunger to dislodge the plunger from the aperture, a shaft connected to the other end of said arm and having said foot engageable means thereon, said shaftbeing rotatably supported on said upper member.

18. A pogo stick according to claim 17 in which said foot engageable means comprise foot rests pivotally 13. A pogo stick comprising: an upper tubular memher having hand graspable means on the upper end and foot engageable means on the lower end, a lower member having ground engaging means on the lower end and having the upper end extending into the lower end of said upper member in slidable telescopic relation thereto, a spring extending axially in said upper mem- .mounted on the ends of said shaft for movement between horizontal working positions and vertical idle positions.

19. A pogo stick according to claim 17 which includes a further spring urging said spring arm toward ineffective position, and adjustable means operatively engageable with said spring arm to move said spring arm into effective plunger dislodging position.

20. A pogo stick according to claim 13 which includes cooperating elements of abutment means on said upper and lower members to limit the extended position thereof.

21. A pogo stick according to claim 13 which includes means preventing relative rotation of said members. 

1. A pogo stick comprising, in combination, an upper tubular member having hand graspable means on the upper end and tiltable foot engageable means on the lower end, a lower tubular member having ground engaging means on the lower end and having the upper end extending into the lower end of said upper tubular member in slidable telescopic relation thereto, a spring in said upper tubular member bearing axially between said tubular members and urging the tubular members toward extended positions, adjusting means for adjusting the bias exerted by said spring on said tubular members, said adjustment means including a slidable plate mounted iN the upper tubular member and forming a bearing for the adjacent end of said spring, an axial screw rotatably but nonaxially movable connected at one end to one of said tubular members and threadedly engaging said plate, means for preventing rotation of said slidable plate within said upper tubular member, said rotation preventing means including a spring disposed in a groove in said plate in such manner as to engage the interior of the upper tubular member in such manner as to prevent rotation of the plate and actuating means for rotating said screw to adjust said slidable plate axially in said upper tubular member and thereby adjust the bias of said spring on said tubular members.
 2. A pogo stick according to claim 1 wherein the actuating means includes manual means connected to said screw and carried by said upper tubular member for rotating the screw relative to said slidable plate.
 3. A pogo stick according to claim 2 in which said manual means includes means extending through said hand graspable means and operatively connected to said screw for selectively rotating said screw and for permitting said screw to rotate relative to said hand graspable means.
 4. A pogo stick according to claim 1 wherein the actuating means includes ratchet drive means connected to said screw and responsive to relative axial movement of said tubular members for rotating said screw relative to said slidable plate.
 5. A pogo stick according to claim 4 which includes slip clutch means in the connection of said drive means to said screw and slipable at a predetermined torque.
 6. A pogo stick according to claim 4 in which said drive means is reversible.
 7. A pogo stick according to claim 4 in which said drive means includes means for selective adjustment thereof into ineffective position and into position to drive said screw in either direction.
 8. A pogo stick according to claim 4 in which said drive means includes an axially extending spiral strip connected at one end to the end of said screw opposite the end thereof connected to said one member, an element having a slot engaged by said spiral strip and nonaxially moveably connected to the other of said members, and a one-way clutch connecting said element and the other of said members.
 9. A pogo stick according to claim 8 in which said clutch is reversible and includes a selector adjustable into a position for each drive direction of said clutch and into a position wherein said clutch is ineffective in both directions.
 10. A pogo stick according to claim 9 in which said slip clutch means is interposed in the connection of said strip to said screw.
 11. A pogo stick according to claim 1 which includes latch means selectively operable by tilting said foot means for latching said upper and lower members together in a predetermined position near the position of maximum telescopic engagement thereof.
 12. A pogo stick according to claim 11 in which said latch means comprises a spring biased plunger on said lower member and an aperture in said upper member engageable by the plunger, a spring arm having an element on one end engageable with said plunger to dislodge the plunger from the aperture, a shaft connected to the other end of said arm and having said foot engageable means thereon, said shaft being rotatably supported on said upper member.
 13. A pogo stick comprising: an upper tubular member having hand graspable means on the upper end and foot engageable means on the lower end, a lower member having ground engaging means on the lower end and having the upper end extending into the lower end of said upper member in slidable telescopic relation thereto, a spring extending axially in said upper member, a plate non-rotatably but recipocablly mounted in said upper member and engaging one end of said spring, a ratchet assembly engaging the other end of said spring, said ratchet assembly having a first nonrotatable part and a second part rotatable on the first part and cooperating elements of a ratchet on said parts, said second part having a diametral slit therein, a screw extending axially of said upper member and threadedly engaging said plate, one end of said screw being rotatably but nonaxially moveably connected to one of said upper and lower members and said first part of said ratchet assembly being fixed to the other of said members, a spiral strip having one end reciprocably but nonrotatively engaging said slit in said second part of said ratchet assembly and means drivingly connecting the other end of said strip to the free end of said screw.
 14. A pogo stick according to claim 13 which includes means moveable on said upper member and operable to adjust said elements of a ratchet relatively to permit free rotation of said second part on said first part in both directions or to permit free rotation of said second part on said first part in a respective direction while preventing rotation thereof in the opposite direction.
 15. A pogo stick according to claim 13 which includes means selectively operable for manually rotating said screw.
 16. A pogo stick according to claim 13 which includes latch means selectively operable for latching said upper and lower members together in a predetermined position near the position of maximum telescopic engagement thereof.
 17. A pogo stick according to claim 16 in which said latch means comprises a spring biased plunger on said lower member and an aperture in said upper member engageable by the plunger, a spring arm having an element on one end engageable with said plunger to dislodge the plunger from the aperture, a shaft connected to the other end of said arm and having said foot engageable means thereon, said shaft being rotatably supported on said upper member.
 18. A pogo stick according to claim 17 in which said foot engageable means comprise foot rests pivotally mounted on the ends of said shaft for movement between horizontal working positions and vertical idle positions.
 19. A pogo stick according to claim 17 which includes a further spring urging said spring arm toward ineffective position, and adjustable means operatively engageable with said spring arm to move said spring arm into effective plunger dislodging position.
 20. A pogo stick according to claim 13 which includes cooperating elements of abutment means on said upper and lower members to limit the extended position thereof.
 21. A pogo stick according to claim 13 which includes means preventing relative rotation of said members. 